. Bulletin of the Geological Society of America. Geology. 108 C. H. GORDON—SYENITE-GNEISS (lEOPARD ROCK) FROM CANADA. men, shows this area to be made up of small angular and rounded grains of microcline, between which in places there is a small amount of feld- spar similar to that forming the microperthetic intergrowth observed in the large microcline grains, and which is probably albite. Quartz appears in irregular elongated grains here and there along the granular areas. It has crystallized sharply against the adjoining constituents, fitting closely into their sinuous outlines. Some grains a
. Bulletin of the Geological Society of America. Geology. 108 C. H. GORDON—SYENITE-GNEISS (lEOPARD ROCK) FROM CANADA. men, shows this area to be made up of small angular and rounded grains of microcline, between which in places there is a small amount of feld- spar similar to that forming the microperthetic intergrowth observed in the large microcline grains, and which is probably albite. Quartz appears in irregular elongated grains here and there along the granular areas. It has crystallized sharply against the adjoining constituents, fitting closely into their sinuous outlines. Some grains are long and irregular in shape, while others wliich a})pear similar are resolved in polarized light into two or more grains having slightly difierent orientations. Rows of fluid. FiGX'RE 5.—St'cliofi Tiaiisverse to {granular Bands in ihe coarse Syenite-gneiss. Showing augite crystal broken in the portion projecting into the granular band. Ait ^ augite ; ^/= microcline ; /* = plagioclase ; i? =-quartz ; /"= feldspar. inclusions frequently extend uninterruptedly from one quartz grain to another, while in a few instances they were observed in direct continuity with similar lines of inclusions in the adjoining microcline i)lates. The large microcline and augite grains, which constitute the larger part of the section, are traversed in })laces by a series of irregular cracks, which lie parallel with the lines of fluid inclusions in the quartz. The augite sometimes shows the effects of mechanical movements in the fracturing and breaking of a grain lying in contact with the granular zone. The grain shows fracturing throughout, but the breaking appears. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Geological Society of America. [New York : The Society]
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectgeology, bookyear1890
